import launch
import launch_ros

def generate_launch_description(): 
    """产生launch描述"""
    action_node_turtlesim_node = launch_ros.actions.Node(
        package = 'turtlesim', 
        executable = 'turtlesim_node', 
        output = 'screen'
    )
    action_node_star_controller = launch_ros.actions.Node(
        package = 'turtlesim_star', 
        executable = 'star_controller', 
        output = 'log'
    )

    return launch.LaunchDescription([
        # actions
        action_node_turtlesim_node, 
        action_node_star_controller, 
    ])